1. Field of the Invention
The invention is directed to a method for adjusting the flow and the temperature of wash water when washing out contaminates, such as excess chemicals, from fabric webs in textile processing. In particular, an open-width washing machine is used in which a fabric web is conducted through a plurality of wash tubs connected in series and the warm wash water is conducted through these wash tubs in counter-current flow, whereby the flow and the temperature of the wash water are set.
2. Description of the Related Art
During washing of fabric webs in textile processing, the extent of the wash-out or of what is referred to as the washing action can be monitored with contaminate concentration sensors. For example, such a contaminate concentration sensor is a pH meter or a conductivity sensor that measures the extent of the conductivity of the fabric contaminated with excess chemicals. Such a sensor can be pressed against the fabric upon input into the machine and upon output from the machine. The water flow and the water temperature can thereby be set for a defined value of the desired washing action given a fabric of a defined quality. This, however, is only valid for a single fabric quality, and a different setting of the water flow and of the temperature must be applied given a different fabric quality in order to achieve the corresponding washing action.
In general, the water flow and water temperature is set at an excess of water and at a higher than needed temperature that are so broadly dimensioned that the desired washing action is achieved for all fabric qualities. Considerable energy is required for this washing process given the excess flow rate setting and high temperature setting to bring the rinse water, or wash water, and the fabric to be washed up to temperature, to maintain the required temperatures, i.e. to compensate energy losses that occur, and to drive the machines.
Practice has shown that the thermic yield of the washing process is frequently not optimum. The desired washing action, namely, can be achieved in various ways, whereby the following are valid at the extremes: (a) a great quantity of water and low temperature or (b) little water and a high temperature. In general, the known process is carried out with too much wash water and too high a temperature, this leading to high energy costs. Particularly given increasing (excessively high) temperature, the energy losses (and, consequently, the energy costs) rise exponentially, among other things because the evaporation of the water is far greater at high temperature.